I know the main question it's about DT albums, but I have a more clear idea of his voice's progress with his solo albums.. On KITY (
) and Mullmuzzler 2 he has this weak voice, same as the one on FII, but yeah, definitely different from the one on ACOS.. Then, he proved not only he had completely recovered his voice (another one, lol) by the time of recording EOP, but also he was able to sing more difficult songs, with multiple styles (not saying on the previous albums there weren't variation, but most of the songs on them are pretty similar in voice style)..
Then, he strictly kick asses with SI.. You hear "I Need You" and almost cannot believe that he is the singer, and off any fx.. You barely hear him that way on DT songs.. Obviously they're different.. Anyway, I'm glad he has his original voice back by now.. I really hope DT can use it even better the next time.. Maybe helps a little the fact that JLB is starting to composing with the guys..
Oops!.. I realize now I didn't answer the poll question.. Well, I'm not erasing all I wrote.. I think it has already being answered anyway.. Hahaha.. Cheers from Buenos Aires!